| Code | Name | Region |
|---|---|---|
| USCFM | Columbia | MS |
| USCUB | Columbia | NC |
| USYNJ | Columbia | NJ |
| USC73 | Columbia | OH |
| USCKP | Columbia | PA |
| USCAE | Columbia | SC |
| USMRC | Columbia | TN |
| USCB5 | Columbia | VA |
| USCOV | Columbia | WI |
| USCOX | Colmar | PA |
| USCQL | Colo | IA |
| USQLZ | Coloma | CA |
| USCMK | Coloma | MI |
| USOL3 | Colon | MI |
| US2CO | Colona | IL |
| USCZ8 | Colonia | NJ |
| USCNJ | Colonial Heights | VA |
| USCE2 | Colonie | NY |
| US4CL | Colony | KS |
| USCGY | Colony | WY |
| USCOR | Colora | MD |
| USXOY | Colorado City | CO |
| USCXP | Colorado City | TX |
| USKCR | Colorado Creek | AK |
| USCOS | Colorado Springs | CO |
| USCOQ | Colquitt | GA |
| USXEE | Colrain | MA |
| USCS8 | Colstrip | MT |
| USRLR | Colt | AR |
| USCGV | Collegeville | PA |
| USCT2 | Colleyville | TX |
| USG7C | Colliers | WV |
| USCJE | Collierville | TN |
| USCGL | Collingdale | PA |
| USCWD | Collingswood | NJ |
| USXPX | Collins | GA |
| USCL9 | Collins | ID |
| USCNA | Collins | MS |
| USOIX | Collins | NY |
| USOSN | Collinston | UT |
| USOII | Collinsville | AL |
| US775 | Collinsville | CT |
| USYCL | Collinsville | IL |
| USHVC | Collinsville | OK |
| US2CV | Collinsville | TX |
| USOSI | Collinsville | VA |
| USCIW | Collinwood | TN |
| USCQA | Colma | CA |
| USCO6 | Colman | SD |
| USOLX | Colfax | CA |